Diffusion transfer photographic processes and compositions comprising difunctional developers whose terminal moieties couple oxidatively into polymeric dyes



Nov. 3, 1970 s. M. BLOOM 3,537,852

DIFFUSION TRANSFER PHOTOGRAPHIC PROCESSES AND COMPOSITIONS COMPRISINGDIF NAL DEVELOPERS WHOS ERM L MOIETIES COUP D VELY O POLYM C D Filed yl, 8

||\ L SUPPORT |2 -LAYER CONTAINING DEVELOPING AGENT MK PHOTOSENSITIVELAYER I6 I RUPTURABLE CQNTAINER I5 E/ |MAGE RECEIVING LAYER FIG. I I

2|\ ?\-SUPPORT Z I Y 24\ A PHOTOSENSITIVE LAYER 22 M LAYER CONTAININGDEVELOPING AGENT RUPTURABLE CONTAINER k\\ \\W lMAGE RECEIVING LAYER F G.2 I v v A LAYER CONTAINING DEVELOPING AGENT 33\ AND PHOTOSENSITIVESILVER HALIDE RUPTURABLE CONTAINER f -|MA E RECEIVING LAYER *F I G. 3

4|\ 'H/SUPPORT 44- FJPHOTOSENSITIVE LAYER 45 V 1 A RUPTURABLE CONTAINER45 k\\\ \\\:I'QIMAGE REcElvlNG LAYER FIG. 4

INVENTOR. diam/la 772. Mm

m E M ATTORNEYS United States Patent U.S. C]. 96-29 16 Claims ABSTRACTOF THE DISCLOSURE A novel image-forming system comprising forming animagewise distribution of a polymeric dye by the oxidative coupling ofan enamine moiety with an oxidized, hydroxylcontaining silver halidedeveloping radical in a photosensitive element, and forming a transferimage by diffusion of unoxidized developing agent from the unexposedareas and a second oxidative coupling on the image-receiving layer.

This invention relates to photography and more particularly to products,compositions and processes for obtaining color images.

Many systems are known for preparing color images by diffusion transfer.In such prior systems, for example, a photosensitive element containingat least one lightsensitive silver halide emulsion and associated layerof color-providing material, e.g., a complete dye or a color coupler, isexposed and then developed to provide, as a function of development, animagewise distribution of color-providing material which is transferred,by imbibition, to a superposed image-receiving element, e.g., a dyeablesheet material, to provide thereon a monochromatic or multicolor imageof the original subject matter. Many of these prior systems relay forcolor transfer image formation upon mechanisms for providing, as afunction of development, a differential in mobility or diffusibility inthe processing fluid of the color-providing material.

Typical of such systems is the one described in U.S. Pat. No. 2,983,606,issued to Howard G. Rogers, which utilizes a compound called a dyedeveloper which in its oxidized state is less mobile than in itsunoxidized state. Typical color coupling mechanism processes forproviding color images are set forth in U.S. Pats. Nos. 2,661,- 293 and2,698,798, both issued to Edwin H. Land.

The novel image-forming system of the present invention utilizes anoxidative coupling reaction between difunctional compounds to provide acolored, higher molecular weight, substantially nondiffusible reactionproduct as a function of development. This oxidative coupling iseffected between an enamine moiety and a quinone or quinonimine radicalof a silver halide developing moiety. The difunctional compoundpreferably comprises one of each of these moieties in a single molecule.The nonoxidized molecules of the compound containing the developingradical are free to transfer to the image receiving element, where uponoxidation, they similarly undergo oxidative coupling with enaminemoieties. The product formed as a result of said oxidative couplingforms the positive image.

Accordingly, a primary object of this invention is to provide novelprocesses, products and compositions for preparing color images.

Another object is to provide novel products and processes useful forobtaining color images by diffusion transfer.

Still another object is to provide novel systems for obtaining as afunction of development of an exposed photosensitive element, adifferential in the diffusibility or mobility of a color providingmaterial, whereby an imagewise distribution of the mobile colorproviding material is transferred, by imibition, to an image-receivingelement to provide a color transfer image.

Yet another object is to provide novel systems for obtaining both apositive and a negative color transfer image both of which are capableof providing good pictorial information, by the utilization of novelcompounds, which upon development, undergo a chemical interaction toprovide a color forming material in the photosensitive element, andwhich upon oxidation subsequent to diffusion undergo said chemicalinteraction to provide a color forming material on the image-receivingelement.

Other objects of the present invention will in part be obvious and willin part appear hereinafter.

The invention accordingly comprises the several steps and the relationand order of one or more of such steps with respect to each of theothers, and the product possessing the features, properties, and therelation of elements which are exemplified in the following detaileddisclosure, and the scope of the application of which will be indicatedin the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawing wherein:

FIG. 1 is a diagrammatic cross-section of one embodiment of a film unitforming the subject of this invention and illustrates a productcomprising a photosensitive element, a rupturable container and aprint-receiving element;

FIG. 2 is a diagrammatic cross-section of another embodiment of a filmunit wherein the order of the layer containing the developing agent andthe photosensitive layer are reversed in the photosensitive element;

FIG. 3 is a diagrammatic cross-section of still another embodiment of afilm unit forming subject matter of this invention; and

FIG. 4 is a, diagrammatic cross-section of a further embodiment of afilm unit forming subject matter of this invention.

In general, the photographic processes and products disclosed herein areconcerned with the development of. an exposed photosensitive silverhalide layer to provide a colored negative image in the photosensitivelayer and a colored positive image in or on another layer whichcomprises a print-receiving layer. The developing agent which isoxidized as a result of silver development, undergoes an oxidativecoupling and forms a dye image which is coextensive with the silverimage. The unreacted developing agent in the undeveloped areas istransferred, by diffusion, to the print-receiving layer and formsthereon an imagewise distribution of unreacted developing agent which,upon oxidation, undergoes an intermolecular coupling to effect formationof the desired dye image. Oxidation of the transferred unreacteddeveloping agent to cause coupling may be effected by an oxidizing agentincorporated in the print-receiving element or by aerial oxidation.

The term enamine" was coined by Wittig and Blumenthal in 1927 and isused to refer to compounds which are a,fl-unsaturated amines. The termcyclic enamine is Typical examples of cyclic enamine precursors arequaternary pyridine and quinoline derivatives substituted with a methylgroup in the alpha or gamma position. When such compounds are placed inan alkaline environment, the enamine form of the compound is generated.

base on (u e H on 3 2 2 1 CHa 1 CH3 CH3 The term dienamine is defined asa tertiary amine which is :,[3- and gamma,delta-unsaturated. Inprinciple, reactions with cations can take place on the nitrogen (due tostructure I), on the fl-carbon (due to the polarized structure II) or onthe A-carbon (due to III).

(III) Since the term vinylog is used to describe compounds which differby one or more vinylidene linkages, the vinylog of an enamine has thestructure the same as a dienamine.

In this application, the term enamine is intended to include not onlyenamines but also dienamines, and the enamines will be generated fromthe disposition preferably of cyclic as opposed to acyclic quaternaryammonium compounds in a basic medium such that the enamine structure isgenerated in situ. Further information on enamines will be found in anarticle by J. Szmuszkovicz in Advances in Organic Chemistry, Methods andResults, vol. 4, 1963, published by Interscience, New York, N.Y. Furtherinformation on the principle of vinylogy will be found in AdvancedOrganic Chemistry by Reynold C. Fuson, copyright 1950, published by JohnWiley and Son, New York, N.Y.

It must be appreciated, however, that the mere placement of an alpha orgamma substituted methyl quaternary ammonium compound in a given amountof alkali will not automatically generate the enamine derivative. Thegeneration is dependent upon the acid strength of the compound. By thisis meant the ability of a fixed amount of alkali to remove a protontherefrom. Thus, if one mole of methyl pyridine and one mole of alphapicolinium compound were placed in the same amount of NaOH, since theenamine generation is an equilibrium reaction, it would be found thatthe methyl pyridine would display the properties of methyl pyridine,while alpha picolinium compound would display the properties of itsenamine derivative due to the inherent difference in acid strengths.Methyl pyridine will likewise generate is enamine, but only upon anincrease in the concentration of alkali.

The term nondilfusible as used herein has the meaning commonly appliedto the term in color photography and denotes materials which, for allpractical purposes, do not migrate or wander through organic colloidlayers such as gelatin, in the presence of an aqueous alkalineprocessing solution, within a predetermined processing period. The samemeaning is to be attached to the term imm0bile." The term ditfusible asapplied herein has the converse meaning and denotes materials which havethe property of diffusing effectively through colloid layers in thepresence of an aqueous alkaline processing solution. Mobile has the samemeaning.

The term oxidative coupling is used to describe the reaction wherein anoxidized molecule interacts with another (unoxidized) molecule of thesame species or with a molecule of another species. In more detail, theprocedure entails the oxidation of an organic compound, such as phenol,whereby a reactive electron pair generated therefrom may attack anothermolecule of the same species to form a dimeric structure containing afree radical which, if not capped by an atom of hydrogen after formingthe dimer, is capable of continuing the propagation of the chain to forma relatively high molecular weight homopolymeric product. In otherinstances, the reactive electron pair can be generated not from themoiety which is oxidized, but from another moiety.

In the processes of this invention, a quaternary ammonium radical formsits enamine derivative which as is known, contains a reactive electronpair in the alkaline processing solution. When the silver halidedeveloping agent, usually a hydroquinone, i.e., a substituted phenol, isoxidized, the reactive electron pair attacks the ring to form a newcarbon to carbon bond. Since more than one enamine radical is present,the reaction is capable of continual propagation to form a relativelyhigh molecular weight product. It is seen that since the hydroquinoneradical is only oxidized in the areas of development, the formation ofthe high molecular weight nondiffusible product occurs as a function ofdevelopment. By careful selection of the entire moiety that contains theenamine radical, it is possible to form a chromophore upon theinteraction with the developing radical and provide a colored image.

In the preferred mode of this invention, both the quaternary ammoniumradical and the silver halide developing radical comprise parts of onemolecule. These two radicals are joined by a linking group.

While it is not intended to be restrictive to any particular theory, itis believed that the reaction mechanism upon which image formation ispredicted in both the photosensitive element, i.e., negative image, andthe imagereceiving layer, i.e., positive image, may be illustrated bythe following reaction between the enamine moiety and the oxidizedsilver halide developing radicals, herein illustrated as a quinonylradical derived from a hydroquinone.

I OH I (9, and comprise resonance forms of a chromophore which is amerocyanine dye.

It is to be noted that if the oxidized developing radical is halogensubstituted, such as a chloroquinone, the chlorine is replaced todirectly form the chromophore without the need for the intermediatesteps.

Since the enamine radical is double ended, i.e., attached to anotherenamine radical, or preferably attached to a developing radical, it isseen that a colored immobile polymer is built up as a function ofdevelopment in the photosensitive layer.

A colored positive image is formed in the imagereceiving layer in theareas corresponding to the undeveloped areas of the photosensitivelayer, since unoxidized developing radicals from such areas, transfer tothe image-receiving layer, become oxidized in the manner previouslydiscussed and then undergo the same oxidative coupling reaction to forma colored polymer.

The preferred compounds utilized in the present invention thus aredefined as being within the structure:

DEVLINKEN wherein DEV is an unsubstituted, alkylsubstituted or halo gensubstituted monovalent radical selected from the group consisting ofphenyl and naphthyl rings, substituted in ortho or para positions withrespect to each other by -OH and -NH at least one of said positionsbeing substituted by -OH; or the precursors thereof, wherein theprecursor group for OH is an alkoxy or alkoxymethoxy group, and theprecursor for NH is 2;

LINK is a divalent linking radical of the formula:

A CH --[OC H 2]n 2 or of the formula:

-A -CH [SC H ]m[CH2]1r z wherein A is selected from the group consistingof oxygen or sulfur, e is l or 0, m is a number of from 0 to 4inclusive, n is a number of from 0 to 8 inclusive, the sum of m-l-nbeing not greater than 8; and

EN is a cyclic 0r acyclic quaternary ammonium radical which is capableof generating an enamine and which radical in bonded through thepentavalent nitrogen atom thereof to LINK.

As examples of useful dihydroxyphenyl radicals comprising DEVsubstituents, mention may be made of orthodihydroxyphenyl,para-dihydroxyphenyl and nuclear-substituted derivatives thereof, e.g.,chloro, methyl, phenyl, and/or methoxy-substituted derivatives thereof,particularly nuclear-substituted p-dihydroxyphenyl such asmethylhydroquinonyl, p-methylphenylhydroquinonyl, chlorohydroquinonyl,methoxyhydroquinonyl, 2,6-dimethylhydroquinonyl,2,6-dimethoxyhydroquinonyl, 2-methoxy-6- methylhydroquinonyl,2,3-dimethylhydroquinonyl, 2,5,6- trimethylhydroquinonyl, etc.

As examples of useful dihydroxynaphthyl silver halide developingradicals comprising DEV mention may be made of any of the abovedihydroxyphenyl radicals Wherein the benzene ring is replaced by anaphthalene ring and the other substituents are appropriately situated.

As examples of useful dialkoxyaryl and dialkoxymethoxyaryl radicals forthis invention, mention may be made of the above dihydroxyphenylradicals wherein the hydroxyl groups are replaced by alkoxy andmethoxyalkoxy groups containing from 1 to 5 carbon atoms in the alkoxyportions, and the aryl ring is either a benzene ring of a naphthalenering.

As examples of useful nitrogen containing silver halide developingradicals, mention can be made of any of the above-mentioneddihydroxyaryl radicals wherein one of the hydroxyl groups is replaced byan --NH group. The precursors for such nitrogen containing developingradicals are those radicals which contain an NO group ortho or para tothe hydroxyl precursor group. As examples of such nitroalkoxyaryl andnitroalkoxymethoxyaryl radicals, mention may be made of 2 nitro, 5ethoxy benzene and any of the dihydroxyaryl radicals above wherein onehydroxyl group is replaced by a nitro group and the other hydroxyl groupis replaced by an alkoxy or alkoxymethoxy group.

LINK, the divalent linking radical of the formula indicated above,comprises a unit, A --CH wherein A has been previously defined, joinedto a linear divalent hydrocarbon group, or a linear divalent hydrocarbongroup interrupted by atom(s) of sulfur or oxygen such that ether orthioether linkages are formed. The proviso exists that there must be atleast two carbon atoms interspaced between the last oxygen or sulfuratom and the moiety --EN.

As illustrations of suitable alkylene radicals comprehended as thelinear divalent hydrocarbon portion of LINK, mention may be made ofradicals such as As examples of some hydrocarbon substituents containingunsaturation that are suitable for such portion of LINK, mention can bemade of radicals such as E and As examples of linear divalenthydrocarbon groups that are interrupted by atom(s) of oxygen or sulfur,mention may be made of CH -O-CH -CH As has been indicated, EN is aquaternary ammonium radical which is capable of generating an enamine.While the EN moiety can be either cyclic or acyclic, the more preferredmoieties are cyclic.

Quaternary ammonium compounds are organic compounds which contain apentavalent nitrogen atom. Generally, they can be considered asderivatives of ammonium compounds wherein the four valences usuallyoccupied by the hydrogen atoms are occupied by organic radicals.Generally, the organic radicals are joined directly to the pentavalentnitrogen through a single or double carbonto-nitrogen bond. The term,quaternary ammonium, as used in this application, is intended to includecompounds wherein the pentavalent nitrogen is one of the nuclear atomsin a heterocyclic ring, and such heterocyclic quaternary ammoniumcompounds are preferred. It will be seen that the other atoms comprisingthe heterocyclic ring can be either all carbon atoms, as well as carbonatoms interspaced with atoms of sulphur, selenium, oxygen and nitrogen.It will be further seen that the term heterocyclic ring is intended toencompass not only single ring structures but also fused rings, such asquinoline. It is seen that EN, to be able to generate an enamine, mustcontain, when cyclic, a carbon atom alpha to the nitrogen atom withinthe ring which has bonded thereto an alkyl group not in the ring whichcontains at least one hydrogen atom, or EN can be a vinylog thereof. Asimilar relationship exists for acyclic EN moieties.

As examples of compounds within the formula:

DEVLINKEN wherein DEV and LINK are as previously defined, mention may bemade of those represented by the following formulae:

and

l TX- wherein Q is an acyclic hydrocarbon or halogen substitutedhydrocarbon group, M represents the atoms necessary to complete aheterocyclic ring, X is an anion, e.g., methylsulfonate, bromide,chloride, toluene sulfonate, etc., and T is an alkyl radical.

Typical quaternary ammonium radicals which are capable of generating anenamine and which contain only carbon atoms and the tertiary nitrogenatom within the heterocyclic ring include alpha picolinium, gammapicolinium, alpha qicolinium, gamma quinolinum and l-methylisoindolenine.

Quaternary ammonium radicals which are capable of generating an enamineand which contain in addition to carbon atoms and a tertiary nitrogenatom within a heterocyclic ring, other atoms such as an atom ofselenium, oxygen, sulfur or an additional nitrogen atom can be employedin the present invention as EN. Such radicals include those derived fromthe thiazole, selenazole, oxazole, imidazole and indole ring systemsamong others.

The anion represented by the designation X in the formulae comprisesthose anionic acid radicals customary in the cyanine dye art, forexample, chloride, bromide, iodide, methylsulfate, ethylsulfate,p-toluenesulfonate, benzenesulfonate, acetate, propionate, cyanate,perchlorate, and the like.

While the acyclic alkyl group bonded to the alpha carbon can contain anynumber of carbon atoms provided that the unreacted enamine is capable ofdiffusing, it is preferred to use a methyl, ethyl or propyl group.

It should be apparent from above that any LINK substituent thatcomprises purely hydrocarbon units contains at least two carbon atoms inthe chain. This is necessary to avoid cleavage of the molecule when itis placed in a strong alkaline environment. If oxygen or sulfur atomsare present in the chain, there should not be an atom of one of thesebonded to the same carbon atom as is bonded to the pentavalent nitrogenatom of EN; nor should such an atom be bonded directly to EN. Here, too,the necessity for two carbon atoms between such oxygen or sulfur atomsis to avoid cleavage in an alkaline medium.

As examples of compounds within the scope of the above formula:

DEVLINKEN suitable for use in this invention, mention may be made of thefollowing:

CH3 OH CH2CH2-CH2-N I OH CHa O C211 J 0 CH3 (I) CHa CHzCHa I H3 0 OH2 COHa CH3 C2115 OOH:

OCN"

Compounds of the structure:

DEV--LINK-EN can be prepared among other ways by the alkylation of anamine. This method of preparation forms part of the subject matter of mycopending application Ser. No. 741,293, filed concurrently herewith.

While that application relates to the preparation of compounds of theformula:

it is seen that the compounds of the instant invention comprise asubgenus thereunder. The method disclosed therein comprises reacting atertiary amine which has on the ring carbon atom alpha the nitrogenatom, a carbon atom which for cyclic compounds is located outside thering and which has at least one hydrogen atom bonded thereto, such asZ-methyl pyridine, i.e., alpha picolinc, or a vinylog of such acompound, with a halogen substituted alkyl acetal, such as one of theformula:

CHzBr [CHziv HaOO OOHa wherein y is aninteger of from 1 to 5 inclusive.This intermediate product is reacted with hydrogen ion, such that thealdehyde derivative is prepared. This aldehyde compound is reacted inbase with an acetophenone such as the compound of the formula:

OCHa

I OCHa to give rise to a product of the formula:

0on3 CH3 which can then be reduced, such as by hydrogen, to adialkoxyphenyl quaternary ammonium compound:

0 CH3 I E (LCHs 1 l absence of heat, so as to avoid side reactions. Thisreaction can be illustrated as follows. A compound of the formula:

merril I \J[CH2IZX I 1i[CH2]yU wherein y is as previously defined, z isan integer of from 2-10 inclusive and X is halogen,

or CH SO etc., or its ortho dialkoxy equivalent, is reacted with atertiary amine, as for instance a compound of the formula:

gig)

and a product of the formula: 20

is obtained. Dealkylation of the alkoxy groups prepares the dihydroxycompound.

Compounds containing the optional A group, namely an atom of oxygen orsulfur and an all hydrocarbon remainder of LINK, are prepared by aslightly different alkylation process. This is necessary in view of thefact that the dihydroxy compounds cannot be prepared by theaforementioned synthesis in view of the inability of any reagent todifferentiate between the alkoxy groups in the 2,5 positions and thealkoxy group that would be in the 1 position. Therefore, to preparecompounds containing the optional A group, an alkoxyalkoxy compound suchas the one of the formula:

o cmowmhn or its ortho equivalent, wherein A, y and z are as previouslydefined, is reacted with a compound such as toluene sulfonyl chloride inan organic base such as pyridine to prepare an intermediate of theformula:

pcmo orm u O CHzOlCHzh-H which is then reacted with any tertiary amine,properly substituted, e.g., 2-methyl quinoline, to yield an end productof the formula:

( clamor-121,11

Treatment of the above with dilute mineral acid removes the alkoxymethylgroups and gives the dihydroxy product. Compounds which contain ether orthioether groups in the remainder portion of LINK, i.e., that portion ofLINK which follows the moiety A CH are prepared by treating compounds ofthe following formulae:

y and A are as defined previously, or their ortho equivalents with areagent such as sodium hydride in dimethylsulfoxide followed by theaddition of one mole of ethylene oxide or its sulfur counterpart. Morethan one ether or thioether units can be added to increase the size ofR, by increasing the number of moles of ethylene oxide or ethylenesulfide added in the addition step. The preferred mode, however, is theunimolar addition followed by a sodium hydride treatment between theadditions of each mole of ethylene oxide or sulfide. Following theaddition of the ether units to the starting materials, the samealkylation processes are carried out, as well as same treatment toremove the alkoxymethyl groups.

While the above synthesis has employed ethylene oxide, it is of courseunderstood that other epoxide units such as propylene oxide etc., can beadded in like manner.

The removal of the protective alkoxy groups to form the desired hydroxysubstituted compounds may be accomplished by known hydrolysistechniques. A typical demethylation process involves complexing thegroup to be removed with boron tribromide, followed by decomposition ofthe resulting complex with water. Another demethylation processcomprises treatment of the methoxy intermediate with aqueous HBr or HBrin acetic acid.

The various reaction conditions, e.g., time, temperature, pressure,selection of solvents, etc., for the DEV LINKEN compounds are notcritical to the practice of this invention unless so indicated and willtherefore be readily selected by the skilled artisan in the light of theforegoing descriptive material. The essence of the invention is,therefore, the aforementioned selection of steps, in the order describedto obtain the desired end product, as well as the end product itself.

A further understanding of the invention will be gained from aconsideration of photographic products useful for carrying it intoeffect. In this regard, there is schematically shown in FIG. 1 a filmunit making use of a photosensitive element 10 comprising a support 11of paper or film base material upon which there is mounted, in the ordernamed, a layer 12 comprising a developing agent of the character withwhich this invention is concerned, and a photosensitve layer 14 ofsilver halide. Layer 12 is penetrable by the liquid processingcomposition employed so that the developing agent contained therein maybe placed in solution. The film unit of FIG. 1 also employs aprint-receiving element 15 comprising an image-receiving layer which isliquid permeable and dyeable from alkaline solutions and which has beenillustrated for purposes of simplicity as comprising a single sheet, forexample, paper but may comprise a support 13 upon which is mounted atleast one liquid-permeable and dyeable layer.

As shown in FIG. 1, the photosensitive element and the print-receivingelement 15, for the purpose of positive image formation, are adapted tobe placed in superposed relation with the photosensitive layer orstratum 14 next to the print-receiving layer of element 15.

Also, in the film unit of FIG. 1, a rupturable container 16 adapted tocarry an alkaline solution or liquid composition, is shown as positionedtransversely of and adhered to the print-receiving element 15. Ifdesired, the container 16 may be adhered to the photosensitive layer.Container 16 is of a length approximating the width of the film unit andis constructed to carry suflicient liquid' to effect negative imageformation in an exposed image area of the photosensitive layer 14 andpositive image formation in the corresponding image area of theprintreceiving element 15. In use, the container 16 is adapted to bepositioned between the print-receiving element and the photosenstiveelement so that it will lie adjacent the edges of the correspondingimage areas of these elements which are to be processed by the liquidcontents of the container.

In addition to the alkaline material, the processing composition mayinclude viscosity-increasing film-forming reagents such as hydroxyethylcellulose, sodium carboxymethyl cellulose, etc., and additional reagentsperforming specific desired functions, e.g., antifoggants, etc., itbeing understood that any of these ingredients may be present initiallyin the film unit, in which case the processing composition is formed bycontacting the film unit with the aqueous alkaline material. In anyevent the processing composition may, if desired, be confined in afrangible container or pod such as described, for example, in U.S. Pat.Nos. 2,543,181 and 2,634,886, both issued to Edwin H. Land.

While a liquid container 16, which has been illustrated with the filmunits of this invention, provides a convenient means for spreading aliquid composition between layers of a film unit whereby to permit theprocessing to be carried out within a camera apparatus, the practices ofthis invention may be otherwise effected. For example, a photosensitivelayer, after exposure in suitable apparatus and while preventing furtherexposure thereof to actinic light, may be removed from such apparatusand permeated with the liquid processing composition as by coating thecomposition on the photosensitive layer or otherwise wetting the layerwith the composition, following which the permeated layer, still withoutexposure to actinic light, is brought into contact with aprint-receiving element for image formation in the manner heretoforedescribed.

It is also to be kept in mind that the invention may be successfullypracticed without the use of a film-forming material in the liquidprocessing reagent. As an illustration, with this latter expedient, anonviscous processing composition is particularly applicable and may beapplied to the negative material by imbibition or coating practices andmay be similarly applied to the print-receiving elernent before thelatter and the negative material are brought into superposed relation orcontact for carrying out the transfer of positive image-formingcomponents.

The photoensitive silver halide layers used herein are provided by anyof the conventional silver halide emulsions, e.g., silver chloride,silver bromide, silver bromoiodide, silver chlorobromide or silverchlorobromoiodide. The emulsion layermay also contain the variousadditives heretofore employed in such layers, e.g., optical sensitizers,antifoggants, hardeners, plasticizers, coating aids, speed-increasingmaterials, ultraviolet absorbers, etc. As examples of typical materialswhich may be employed for the support mention may be made of films ofcellulose nitrate, cellulose acetate, polyvinyl acetal, polystyrene,polyethylene terephthalate, polyethylene, polypropylene, etc., paper,glass and others.

The particular sensitivity range of the photosensitive layer -will bechosen to meet to particular requirements of the ultimate usage of theproduct. The silver halide emulsions comprise the photosensitivematerial and other additives, if any, preferably in a matrix or binder.It is preferred to utilize gelatin as the hydrophilic colloid or bindermaterial although such material as polyvinyl alcohol and itswater-soluble derivatives and copolymers, water-soluble polymers such aspolyacrylamide, imidized polyacrylamide, etc., and other water-solublefilm-forming mate rials that form water-permeable coats such ascolloidal albumin, water-soluble cellulose derivatives, etc., can beutilized in preparing the present photographic elements. Compatiblemixtures of two or more of such colloids can also be utilized.

The film unit of FIG. 2 comprises the same elements as are found in thefilm unit of FIG. 1, namely, the photosensitive element, a rupturablecontainer and an imagereceiving element. The photosensitive element 20is formed in a manner similar to the photosensitive element 10 andutilizes substantially similar materials for the purposes ofconstruction. In the photosensitive element of FIG. 2, thephotosensitive layer is coated directly upon the support and followingthe drying of this layer, the layer 12 which contains developing agentis coated upon layer 24. Layer 22, as well as layer 12, of FIG. 1,comprise a carrier such as cellulose acetate hydrogen phthalate, inwhich the developing agent is incorporated. Likewise, the photosensitiveelement 20 is adapted to be used with a print-receiving element 25 ofthe nature disclosed in FIG. 1 and in a similar manner for providing, inthe print-receiving element, a dye image which is the reverse image of alatent silver halide image formed in the photosensitive element 20 uponexposure thereof.

The photosensitive element of FIG. 3 is formed in a similar manner tothe elements of FIGS. 1 and 2, and it uses substantially similarmaterials for the purpose of construction. It, too, is adapted to usewith an image or printreceiving element. In this embodiment of theinvention, the developing agent and the photosensitive silver halidegrains are incorporated into the same layer, 33.

A suitable carrier material for layer 33 is one which, when subjected tohydroxyl ion or alkaline liquids, will swell sufficiently to release thedeveloping agent contained therein. Examples of carriers includegelatin, zein, polymethacrylic acid, shellac and cellulose acetatehydrogen phthalate.

FIGS. 1, 2 and 3 illustrate constructions wherein the developing agentis located in a stratum in front or in a stratum in back of thephotosensitive layer, i.e., in back being between the photosensitivestratum and the support of the photosensitive element. FIG. 4illustrates an embodiment wherein the developing agent is located in theprocessing composition found in the rupturable container 46.Photosensitive element 40 comprises a support 41 upon which is found alayer 44 containing photosensitive silver halide.

The film units depicted in FIGS. 1, 2, 3 and 4 are all adapted forproviding in their image-receiving elements, a colored image which isthe reverse image of a latent silver halide image formed in theirrespective photosensitive elements upon exposure thereof.

The image-receiving material of the positive element 15 includes anymaterial dyeable from alkaline liquid. The positive elements 15, 25, 35and 45 may, as shown, comprise single sheet of permeable material or itmay comprise a support which carries a layer or a stratum of a permeableimage-receiving material. An example of such is imbibition paper orbaryta paper or conventional film base material upon which a permeablestratum is coated. As a further example, the print-receiving element maycomprise a paper support subcoated with a substantiallywater-impermeable material such as a cellulose ester, i.e., cellulosenitrate, cellulose acetate and the like, and having a stratum of apermeable and dyeable material coated over the subcoat.

Image-receiving materials of a dyeable nature, in addition to thosealready named, include gelatin, regenerated cellulose; polyvinylalcohol, partially hydrolyzed polyvinyl acetate; nylons; sodiumalginate; cellulose ethers; such as methyl cellulose or other cellulosederivatives such as sodium carboxymethyl cellulose or hydroxyethylcellulose; papers; proteins, such a glue; carbohydrates, such as gumsand starch; and mixtures or such materials where they are compatible.Polyvinyl alcohol may be named as a preferred image-receiving material.

Particularly useful image-receiving layers comprise m1x tures ofpolyvinyl alcohol or gelatin and poly-4-vinylpyridine (such receivinglayers are disclosed and claimed in U.S. "Pat. No. 3,148,061, issuedSept. 8, 1964 to Howard C. Haas).

It will be noted that other materials useful in the diffusion transferprocesses may be incorporated into the image-receiving layer or one ofthe other layers of the image-receiving element. As an example of such amaterial, mention may be made of development restrainers such as1-phenyl-S-mercaptotetrazole.

It will be apparent that, by appropriate selection of theimage-receiving layer and support from among suitable known opaque andtransparent materials, it is possible to obtain either a coloredpositive reflection print or a colored positive transparency.

When any of the photosensitive elements such as those illustrated inFIGS. 1-4 are exposed and then processed by spreading an aqueousalkaline processing composition between the thus exposed element and animage-receiving layer or dyeable stratum shown as integrated into theimage-receiving elements 15, 25, 35 and 45, a positive colored transferimage is obtained in addition to the colored negative image.

The silver developing radicals, here hydroquinone, is oxidized toquinone in these area of development. The quaternary ammonium radical ispresent in an alkaline environment of suflicient concentration such thatthe enamine derivative is generated. This active methylene group attacksonly the quinone and not the hydroquinone to form a higher molecularweight product by a mechanism known as an oxidative coupling, whichproduct contains an active methylene group that can in turn continue toattack a quinione radical such that an imagewise distribution of a stillhigher molecular weight nondiffusible product is formed as a function ofdevelopment. Since in the preferred embodiment, the quinone and theenamine are part of the same molecule, it is seen that a polymericproduct containing a continuously repeating unit is formed. Since thisrepeating unit is itself a chromophoric group, the negative image willbe colored. It is likewise seen that by varying the nature of thequaternary ammonium radical, a different chromophoric group will becreated, giving rise to various color images It is likewise apparentthat by the choice of particular enamine generators, that yellow, cyanand magneta chromophoric groups can be created and as such will findutility in a multicolor photographic process.

It is likewise seen that by appropriate choice of enamine generators amixture of chromophoric groups can be created such as to give rise toblack images.

Positive image formation is obtained by transferring by imbibition atleast a portion of the imagewise distribution of unoxidized developingagent and enamine generator to a superposed image-receiving layer. Sincein the preferred embodiment both of these moieties form parts of thesame molecule, it is seen that the problem of insuring that bothmoieties transfer to said image-receiving is alleviated. At the site ofpositive image formation, the transferred unoxidized developing agent isoxidized and thus will be subject to attack from active methylene groupsnow present from the enamine generator which has also transferred tosaid image-receiving layer. This oxidation can take place from thepresence of oxidizing agents in the image-receiving element, or at theend of the predetermined imbibition period when the image-receivingelement is separated from the superposed photosensitive layer via theoxygen in the air. Since the polymeric product is now formed in theimage-receiving element, a colored image is obtained due to the presenceof the chromophoric repeating unit. It is readily seen that the color ofthe negative image and the positive image will be same.

Control of pH is very important to the formation of both the negativeand positive images of the present invention. A highly alkalineenvironment is necessary for the generation of the enamine derivative ofthe quaternary ammonium radical and also for the oxidative couplingreaction to form the colored polymeric reaction product. By maintaininga high pH in the image-receiving layer, the unoxidized developingradicals which have transferred thereto, by imbibition, can afteroxidation also enter into the oxidative coupling reaction with generatedenamine moieties found in the image-receiving layer, whereby a coloredpolymeric positive image is formed.

It is to be seen that the image-forming system of the present inventiongives rise to a negative image from which high quality informationreadout can be obtained. This is due to the fact that the image isderived from two sources, namely the imagewise distribution of developedsilver, and polymeric dye of the oxidative coupling. Since the epsilonof the dye formed and the covering power of the developed silver arecumulative, it is seen that for a given amount of exposure, a negativeimage of greater than normal density will be obtained.

The invention will be illustrated in greater detail in conjunction withthe following specific examples which set forth representativepreparations of the novel silver halide developing compounds of thisinvention, which preparations are not, however, to be limited to thedetails therein set forth and are intended to be illustrative only.

EXAMPLE 1 Preparation of N-'y-(2',5' dihydroxyphenyl)propyl 4-methylquinolinium bromide The 3-(2',5-dimethoxyphenyl)propanol, 340 g.,0.2 mole, was dissolved in 400 ml. of ethanol. Sodium borohydride, 7.4g., 0.2 mole, was added and the reaction mixture refluxed two hours. Thesolvent was removed in vacuo and water and ethyl ether were added. Theether extract was washed with water, dried (anhydrous magnesium sulfate)and concentrated ot a heavy oil. The oil, 27 g., 79%,3-(2',5'-dimethoxyphenyl)propanol was used directly. An infraredanalysis showed that no aldehyde remained unreacted.

The 3-(2',5'-dimethoxyphenyl)propanol, 27 g., 0.137 mole, was cooled to-10 and phosphorus tribromide 20 g., 0.074 mole, was added dropwise withstirring. The reaction was allowed to rise to room temperature and wasstirred for an additional two hours and finally heated at 80 for /2hour. The reaction mixture was poured into ice water and the productextracted into ethyl ether. The ether was washed with water and dried.The crude 3-(2',5- dimethoxyphenyl)propyl 'bromide was obtained byremoval of the ether.

Attempts to purify a sample of the crude product by distillation at 18mm. pressure and a temperature of C. gave a clear liquid which waslargely converted to a methoxy chroman. Because of this sensitivity toheat, the crude product was used directly in the synthesis of thequaternary salt.

The propyl bromide product, 5.6 g., 0.04 mole, and 4-methylquinoline,5.6 g., 0.04 mole, were dissolved in 40 ml. dioxane and heated on thesteam cone two days. On cooling, two layers were obtained. The dioxanelayer was decanted and ethyl ether-ethyl acetate trituration was used toobtain the product. The crude solid was taken up in 60 ml. ofconcentrated hydrobromic acid and the reaction mixture refluxed 2 /2hours. The HBr was removed by evaporation on the steam cone using anitrogen 1 7 stream. Trituration of the residue with acetone gave 2 g.of N-y (2',5-dihydroxyphenyl)propyl 4 methylquinolinium bromide whichwas crystallized from ethanol, M.P. 23r8-9, and is of the formula:

(IJHa This compound is a vinylog of the Z-methylquinoline compound andis capable of generating an enamine.

EXAMPLE H Utilizing a procedure similar to the one set forth in ExampleI, the compound of the following formula was prepared:

It was a yellowish solid, molecular weight 324, that was soluble inwater and slightly soluble in methyl Cellosolve. The melting point was220-221 C.

EXAMPLE III Utilizing a procedure similar to the one set forth inExample II, the compound N-y-(2',S-dihydroxyphenyl)propyl-Z-methylqtfinolinium bromide was prepared. It was a yellow solid,molecular weight 374, that was soluble in alkali and somewhat soluble inmethyl Cellosolve and ethanol. The melting point was 25225 3 C.

The invention will be illustrated in greater detail in conjunction withthe following specific example which sets forth a representative processand which is not intended to be limiting, but is meant to beillustrative only, of photographic utility of the novel compounds.

EXAMPLE IV A photosensitive element was prepared by coating a gelatinsubcoated film base at a speed of 10 feet per minute with a solutioncomprising 1 g. of a compound of the formula:

tive element and a superposed image-receiving element, said aqueousprocessing composition comprlsin gz The image-receiving elementcomprised a 2:1 mixture of gelatin/poly-4-vinylpyridine containing asmall amount of 1-phenyl-5-mercaptotetrazole coated upon a pigmentedplastic base. After an imbibition period of approximately one minute,the image-receiving element was separated and contained a dense bluepositive transfer image.

Processing can be effected in the presence of an auxiliary oraccelerating silver halide developing agent which is substantiallycolorless, at least in the unoxidized form. Particularly useful aresubstituted hydroquinones, such as phenylhydroquinone, 4'-methylphenylhydroquinone, toluhydroquinone, tertiary-butylhydroquinone,and 2,5- triptycene diol. These hydroquinones may be employed ascomponents of the processing composition or they may be incorporated inone or more layers of the negative. A small amount only of suchauxiliary developing agents should be used in order not to terminate thepolymer chain too early. The color provided by the participation of suchcompound in the oxidative coupling reaction is the same as that providedby the principal developing agent, since the resulting chromophoricgroup is the same.

Modifications of the film structure, in addition to those alreadydiscussed, are included Within the scope of the invention.

It is possible to make two or more transfer prints from thephotosensitive element by employing a quantity of enamine radicals andsilver halide developing radicals in excess of that needed to provide asingle transfer print. By appropriate control of diffusion rates andimbibition time, a quantity of image-forming reagents at leastsufficient for a second transfer print remains in the processedphotosensitive element. The second transfer print may be obtained bypressing the photosensitive element against a new print-receivingelement in the presence of a processing solution effective to transfer asecond imagewise distribution of developing agent and enamine radical.

In all products employed in the practice of the invention, it ispreferable to expose the negative material or photosensitive elementfrom the emulsion side. It is, therefore, desirable to hold thephotosensitive element and positive sheet material together at one endthereof by fastening means, not shown, but comprising hinges, staples,or the like, in such manner that the photosensitive element and thepositive element may be spread apart from their positions illustrated inFIG. 1. When the film unit is of the roll film type, the photosensitiveelement and the positive sheet are wound into separate rolls and thefree ends of said rolls are connected together in the manner described.

This invention is especially useful in composite film units intended foruse in a Polaroid Land Camera, made by Polaroid Corporation, Cambridge39, Mass., or a similar camera structure such, for example, as the rollfilm type camera forming the subject matter of US. Pat. No. 2,991,702,issued to Vaito K. Eloranta on July 11, 1948, or the film pack typecamera shown in US. Pat. No. 2,991,701, issued to Vaito K. Eloranta onJuly 11, 1961. In general, such composite film units comprise aphotosensitive element, an image-receiving element and a rupturable podcontaining an aqueous alkaline processing solution, and may take theform of roll film, sheet film or film packs. The elements and pod are soassociated with each other that, upon processing, the photosensitiveelement may be superposed on the image-receiving element and the pod maybe ruptured to spread the aqueous alkaline processing solution betweenthe superposed elements.

Furthermore, the invention is useful for copying purposes from colorseparation positives with any of the types of film units described. Ofcourse, when the invention is used in the production of photographicoriginals, the spectral sensitivity of the different emulsion layersmust be suitably chosen. For instance, a panchromatic or ared-sensitized silver halide emulsion is preferably employed forproducing a cyan positive image.

The inventive concepts herein set forth are adaptable for multicolorwork by the use of special photographic materials, for example, filmmaterials of the type containing two or more photosensitized layersassociated with an appropriate number of image-receiving layers andadapted to be treated with one or more liquid processing compositions,appropriate enamine generators to impart the desired subtractive colorsbeing incorporated into separate alkali permeable layers of the element.

While the above discussion has referred to oxidative couplings takingplace between an in situ generated enamine moiety and an oxidized silverhalide developing radical, both of which have been shown to be presentas parts of the same molecule, as per the formula:

DEVLINK-EN as defined previously, it will be appreciated that the sameoxidative coupling can take place between molecules of the two compoundsof the formulae:

DEVLINKDEV and EN-LINKEN wherein the moieties DEV, LINK and EN are asdefined in the formula:

DEVLINKEN This latter mechanism can best be utilized for forming colorednegative images of high quality.

Throughout the specification and appended claims the expression positiveimage has been used. This expression should not be interpreted in arestrictive sense since it is used primarily for purposes ofillustration, in that it defines the image produced on theimage-carrying layer as being reversed, in the positive-negative sense,with respect to the image in the photosensitive element. As an exampleof an alternative meaning for positive image, assume that thephotosensitive element is exposed to actinic light through a negativetransparency. In this case the latent image in the photosensitiveelement will be positive and the image produced on the image-carryinglayer will be a negative. The expression positive image is intended tocover such an image produced on the image-carrying layer.

In the preceding portions of the specification, the expression color hasbeen used. This expression is intended to include the use of a pluralityof colors to obtain black, as well as the use of a single black dye.

Since certain changes may be made in the above products, compositionsand processes without departing from the scope of the invention hereininvolved, it is intended that all matter contained in the abovedescription shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. A process for forming images in color, which comprises:

(a) developing an exposed silver halide stratum with an aromatic silverhalide developing agent which contains at least one hydroxyl group inthe developing radical and which agent also contains a substituentcapable of generating an enamine moiety, said developing radical beingcapable upon oxidation of interaction with an enamine by an oxidativecoupling reaction, said silver halide developing agent being present ata pH such that said enamine moiety is generated;

(b) immobilizing said developing agent in developed areas of the silverhalide stratum by reaction of oxid- 20 ized developing radicals withenamine moieties, whereby a nondiffusible dye is formed in saiddeveloped areas;

(c) transferring at least part of the unoxidized developing agent fromthe undeveloped areas of the photosensitive elemeut, by imbibition, toan image-receiving layer in superposed relationship with said silverhalide stratum;

(d) oxidizing the developing radicals transferred; and

(e) reacting the oxidized transferred developing radicals with enaminemoieties to impart to said imagereceiving layer a reverse dye image ofthe developed image.

2. The process of forming images in color as defined in claim 1 whereinthe silver halide developing agent is a compound of the formula:

DEVLINKEN wherein DEV is an unsubstituted, alkylsubstituted or halogensubstituted monovalent radical selected from the group consisting ofphenyl and naphthyl rings, substituted in ortho or para positions withrespect to each other by OH and NH at least one of said positions beingsubstituted by OH; or the precursors thereof, wherein the precursorgroup for OH is an alkoxy or alkoxymethoxy group, and the precursor forNH is NO LINK is a divalent linking radical of the formula:

wherein A is selected from the group consisting of oxygen or sulfur, eis 1 or 0, m is a number of from 0 to 4 inclusive, n is a number of from0 to 8 inclusive, the sum of 121+): being not greater than 8; and EN isa cyclic or acyclic quaternary ammonium radical which is capable ofgenerating an enamine and which radical is bonded through thepentavalent nitrogen atom thereof to LINK. 3. The process of formingimages in color as defined in claim 1 wherein the silver halidedeveloping agent is a compound selected from the group consisting of:

N-y- 2'-5 -dihydroxyphenyl propyl-Z-methylquinolinium bromide;

N y- 2,5 '-dihydroxyphenyl propyl-4-methylquinolinium bromide; and

N-'y-(2,5-dihydroxyphenyl)propyl-alphapicolinium bromide.

4. The process of forming images in color as defined in claim 1 whereinthe image-receiving layer and the silver halide stratum are separatedfrom said superposed relationship at some stage of said process afterthe imagewise distribution of unoxidized developing agent has beentransferred from said silver halide stratum to said image-receivinglayer.

5. A diffusion transfer process comprising the steps of developing anexposed photosensitive silver halide stratum with an aromatic silverhalide developing agent which contains at least one hydroxyl group inthe developing radical and which agent contains a substituent capable ofgenerating an enamine moiety, generating enamine moieties, oxidizingsaid developing agent as a function of development to provide indeveloped areas of said silver halide stratum an imagewise distributionof a substantially nondiifusible polymeric dye by an oxidative couplingreaction, transferring at least a portion of the imagewise distributionof unoxidized developing agent from the undeveloped areas of said silverhalide stratum to a dyeable superposed image-receiving layer, oxidizingthe developing radicals transferred and forming a reverse dye image onsaid image-receiving layer, by an oxidative coupling reaction betweenenamine moieties and the oxidized developing radicals.

6. A diffusion transfer process comprising the steps of developing anexposed photosensitive silver halide stratum with a hydroquinonyl silverhalide developing agent which contains a substituent capable ofgenerating an enamine moiety, generating enamine moieties, oxidizingsaid developing agent as a function of development to provide indeveloped areas of said silver halide stratum an imagewise distributionof a substantially nonditfusible cyanine dye reaction product by anoxidative coupling reaction, transferring at least a portion of theimagewise distribution of unoxidized developing agent from theundeveloped areas of said silver halide stratum to a dyeable superposedimage-receiving layer, oxidizing the developing radicals transferred andforming a reverse dye image on said image-receiving layer, by anoxidative coupling reaction between enamine moieties and the oxidizeddeveloping radicals.

7. The process as defined in claim 5 wherein the imagereceiving layerand the silver halide stratum are separated from said superposedrelationship at some stage of said process after said imagewisedistribution of unoxidized developing agent has been transferred fromsaid silver halide stratum to said image-receiving layer.

8. The process as defined in claim 5 wherein the developing agent is acompound of the formula:

DEV-LINK- EN wherein 'DEV is an unsubstituted, al kylsubstituted orhalogen substituted monovalent radical selected from the groupconsisting of phenyl and naphthyl rings, substituted in ortho or parapositions with respect to each other by OH and NH at least one of saidpositions being substituted by OH; or the precursors thereof, whereinthe precursor group for OH is an alkoxy or alkoxymethoxy group, and theprecursor for NH is N LINK is a divalent linking radical of the formula:

wherein A is selected from the group consisting of oxygen or sulfur, eis 1 or 0, m is a number of from 0 to 4 inclusive, n is a number of from0 to 8 inelusive, the sum of m-l-n being not greater than 8; and

EN is a cyclic or acyclic quaternary ammonium radical which is capableof generating an enamine and which radical is bonded through thepentavalent nitrogen atom thereof to LINK.

9. The process as defined in claim wherein the developing agent isselected from the group consisting of N 'y (2',5' dihydroxyphenyl)propyl4-methylquinolinium bromide, N 'y (2,5' dihydroxyphenyl)propyl-Z-methylquinolinium bromide andN-'y-(2',5'-dihydroxyphenyl)propylalphapicolinium bromide.

10. A process for forming images in color which comprises providing in alayer of silver halide dispersed in a polymeric matrix of aphotosensitive element, which element contains a latent image, asubstantially uniform distribution of a solution of an aromatic silverhalide developing agent which contains at least one hydroxyl group inthe developing radical and which developing agent contains a substituentcapable of generating an enamine moiety, and which developing radical inits oxidized state is capable of interaction with an enamine to form areaction product which is substantially immobile in the photosensitiveelement, generating enamine moieties, developing the latent image andoxidizing said developing radicals as a function of development,interacting oxidized developing radicals with enamine moieties wherebyan imagewise distribution of a polymeric dye is formed in the areas ofexposure and development, and removing at least at part of theunoxidized developing agent from undeveloped areas.

11. A photographic product comprising a photosensitive stratum having aliquid permeable portion, including a layer of a dye free photosensitivesilver halide emulsion comprising silver halide dispersed in a polymericmatrix, an image-receiving layer including a dyeable material forreceiving a transfer image, and a container holding a liquid, saidphotosensitive stratum, said imagereceiving layer and said containerbeing attached together to permit at least a portion of saidimage-receiving layer and said photosensitive stratum to be superposedwith said container so positioned as to be capable of being ruptured andof releasing its liquid content to at least partially permeate saidsuperposed image-receiving layer and said photosensitive stratum,including said emulsion, said product having postioned thereinphotographic processing materials, said materials including an aromaticsilver halide developing agent containing at least one hydroxyl group inthe developing radical, and which agent contains a substituent capableof generating an enamine moiety, and which agent is soluble in saidliquid and when dissolved therein is mobile in said photographicproduct, and wherein said developing radicals are capable upon oxidationthereof, of interaction with said enamine moieties to provide animagewise distribution of a polymeric dye in said photosensitiveemulsions developed areas, said materials being rendered effective uponthe rupture of said container for providing in said emulsion asubstantially uniform distribution of said enamine moieties and saiddeveloping radicals whereby to develop a latent image in said emulsion,form an imagewise distribution of a polymeric dye and provide in saidemulsion unoxidized developing agent in mobile condition andtransportable from said photosensitive stratum to said image-receivinglayer for imparting to the dyeable material a positive dye image havingsubstantially the same color as said negative image.

12. A photographic product as defined in claim 11 wherein saiddeveloping agent is of the formula:

DEVLINKEN wherein DEV is an unsubstituted, alkylsubstituted or halogensubstituted monovalent radical selected from the group consisting ofphenyl and naphthyl rings, substituted in ortho or para positions withrespect to each other by OH and NH at least one of said positions beingsubstituted by OH; or the precursors thereof, wherein the precursorgroup for OH is an alkoxy or alkoxymethoxy group, and the precursor forNH is NO LINK is a divalent linking radical of the formula:

e 2 2 4] m 2] n 2 or of the formula:

A CH [SC2H4] m 11 2- wherein A is selected from the group consisting ofoxygen or sulfur, e is 1 or 0, m is a number of from 0 to 4 inclusive, nis a number of from 0 to 8 isnclusive, the sum of m+n being not greaterthan ;and

EN is a cyclic or acyclic quaternary ammonium radical which is capableof generating an enamine and which radical is bonded through thepentavalent nitrogen atom thereof to LINK.

13. A photographic product as defined in claim 11 wherein the developingagent is selected from the group consisting of N 'y (2,5dihydroxyphenyl)propy1-4- methylquinolinium bromide, N 'y (2',5dihydroxyphenyl)propyl 2 methylquinolinium bromide and N- y (2',5dihydroxyphenyl)propyl alphapicolinium bromide.

14. A photosensitive element comprising a support, at least two liquidpermeable layers mounted upon said support, at least one of which layersis a photosensitive layer comprising silver halide dispersed in apolymeric matrix; at least one of which layers is an aromatic silverhalide developing agent containing at least one hydroxyl group in thedeveloping radical, and further containing 5 a substituent capable ofgenerating an enamine moiety, and which developing radical is capableupon oxidation of interaction with said enamine moiety, wherein saiddeveloping agent is soluble in a liquid processing composition and whendissolved therein is mobile in said element, and wherein said developingagent is characterized by providing upon the development of a latentimage to silver, an imagewise distribution of a polymeric dye in thephotosensitive layer, by the oxidative coupling of oxidized developingradicals with the enamine moieties.

15. A photosensitive element as defined in claim 14 wherein thedeveloping agent is of the formula:

DEVLINK-EN 20 wherein LINK is a divalent linking radical of the formula:

m [C 2] n' 2 or of the formula:

e' 2 l SC2H4] m [CH2] n 2 wherein A is selected from the groupconsisting of oxygen or sulfur, e is l or 0, m is a number of from 0 to4 inclusive, n is a number of from 0 to 8 inclusive, the sum of m-l-nbeing not greater than 8; and

EN is a cyclic or acyclic quaternary ammonium radical which is capableof generating an enamine and which radical is bonded through thepentavalent nitrogen atom thereof to LINK.

16. A photosensitive element as defined in claim 14 wherein thedeveloping agent is selected from the group consisting of N 'y (2',5dihydroxyphenyl)propyl-4- methylquinolinium bromide,N-'y-(2,5-dihydroxyphenyl) propyl-Z-methylquinolinium bromide andN-'y-(2,5'-dihydroxyphenyl)propyl-alphapicolinium bromide.

References Cited UNITED STATES PATENTS 3,309,199 3/1967 Ross 9629 NORMANG. TORCHIN, Primary Examiner A. T. SURO PICO, Assistant Examiner U.S.C1. X.R. 9655 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 3,537,852 Dated November 3, 1970 Inventoi-(s) Stanley M.Bloom It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

Column 16, line 41 (application page 33, line 20) "340 g." should be--34.0 g.-.

Column 16, line 47 (application page 33, line 25) "ot" should be --to-.

Column 18 (application page 38, line 25) delete lines 63, 64 and 65 andsubstitute No. 2,435,717, issued to Edwin H. Land on February 10, 1948,or the film pack type camera shown in U. S. Patent No. 2,991,702, issuedto Vaito K. Eloranta on July ll,.

Column 22, line 1 (application claim 10, line 18) "at", secondoccurrence, should be --a-.

Signed and sealed this 1 8th day of May 1 971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR Attesting OfficerCommissioner of Patents can nnAnzn In cn\

